1. Field of the Invention
The present invention generally relates to a composite structure for light diffusion, and more particularly to a composite structure having improved physical strength and/or light utilization and/or glare reduction for light path modification.
2. Description of the Prior Art
Nowadays the technologies for displaying images, especially applying to the display devices of the portable electronic equipments having low power consumption, are used regularly. Liquid Crystal Display (LCD) is one of the major technologies used in these display devices and an external lighting is necessary thereof. In these portable electrical equipments, batteries are used as the only power source, thus how to enhance the light utilization efficiency becomes important.
For the reason, many techniques for increasing light utilization efficiency are used in LCD display device. As indicated in FIGS. 1A and 1B, a variety of optical materials and structures are typically used in order to improve the overall optical performance of an LCD display device. The light guide includes a miniature fluorescent lamp and reflector. The light from the lamp is totally internal reflected in the light guide before it is reflected by the dots for extracting light from the light guide on the reflecting material. The light from the light guide may then pass through several diffusing materials or light path modifying materials. The light path modifying materials may comprise light diffusion material, prism array, polarizing plate, polarization conversion layer and the like.
The techniques are not only applied in portable electrical equipments but also put in use to image projectors. Some of the most recent developments include DMD (Digital Mirror Device, from Texas Instruments) projectors and LCD projectors. A screen is used to be a media for projecting the final images from these projectors to the viewer. Depending on the viewer's environment and the projection principle used, the screen can either be a “front projection” or “rear projection” type.
Microlens are also widely used in displaying and projection. Reference is now made in FIG. 3, the microlens 12 arranged as an array on a carrier media are illustrated 14. The microlens are fabricated by the molding tool. Considering the difficulty in fabrication process, there are gaps between microlens for decreasing the fault resulted from mold releasing, whereby the light utilization efficiency on the gaps is ignored. Thus more light utilization efficiency can be gained by well using the light on the gaps.